OBJECTIVES: 1. The physiological properties of the spinal cord and its regenerative capacity will be studied in mammals rendered paraplegic by transecting the spinal cord at T5 or by injecting 6-aminonicotinamide, batrachotoxin, or tetrodotoxin into the subarachnoid space. Spinal reflexes, neuromuscular transmission, and membrane properties of slow and fast muscles will be measured to determine: (1) the effect of drugs and toxins that inhibit gliosis; (2) the effect of hibernation (in which glial and connective tissue scarring is suppressed); (3) the effect of toxins which alter the ionic composition of the extracellular space surrounding the neurons; (4) the effect of the hibernating (sleep) factor on the physiological and regenerative properties of the neuronmuscular systems of nonhibernating animals. 2. The relation of axonal transport to the maintenance of the membrane properties of slow and fast muscles will be examined. 3. The interaction between the dystrophic gene and neurotrophic influences will be examined in dystrophic chicken muscle during denervation, reinnervation, and hyperinnervation. The effect of pumiliotoxin (which we have found to suppress the symptomatology of the disease) will be studied. 4. Drugs and toxins such as amantadine, naloxone, quinacrine, atropine, piperocaine , batrachotoxin gephyrotoxin, pumiliotoxin, and histrinonicotoxin will be used to probe the function of the ACh receptor-ionic channel complex. 5. Isolation and purification of ACh receptor and ionic channel proteins have been sufficiently accomplished in our laboratory to enable us to attempt to reconstitute these macromolecules in artifical lipid membranes. Ionic permeability of these functional, ionconducting membranes will be assessed as well as the effects of receptor- and channel-blocking drugs such as those named in item 4.